Cataclysm Classic Shadow Priest Gear and Best in Slot

Slot	Item	Reforge	Source
Helm	Crown of the Twilight Queen	Crit → Spirit	Sinestra (H) The Bastion of Twilight
Neck	Planetary Amulet of the Undertow	–	Al'Akir (H) Throne of the Four Winds
Shoulder	Mercurial Shoulderwraps	–	Al'Akir or Chogall (H) Throne of the Four Winds; (H) The Bastion of Twilight
Cloak	Shroud of Endless Grief	Mastery → Spirit	Sinestra (H) The Bastion of Twilight
Chest	Mercurial Vestment	Crit → Spirit	Halfus Wyrmbreaker (H) The Bastion of Twilight
Bracer	Bracers of the Dark Mother	Mastery → Haste	Sinestra (H) The Bastion of Twilight
Gloves	Mercurial Gloves	Mastery → Haste	Atramedes (H) Blackwing Descent
Belt	Soul Breath Belt of the Undertow	–	Conclave of Wind (H) Throne of the Four Winds
Legs	Mercurial Leggings	–	Maloriak (H) Blackwing Descent
Boots	Einhorn's Galoshes	Mastery → Spirit	Chimaeron (H) Blackwing Descent
Ring 1	Planetary Band of the Undertow	–	Conclave of Wind (H) Throne of the Four Winds
Ring 2	Signet of the Fifth Circle	Mastery → Spirit	Chogall (H) The Bastion of Twilight
Trinket 1	Darkmoon Card: Volcano	–	Darkmoon Volcanic Deck
Trinket 2	Theralion's Mirror	–	Valiona (H) The Bastion of Twilight
Weapon	Incineratus	Mastery → Spirit	Magmaw (H) Blackwing Descent
Off-Hand	Book of Binding Will	Hit → Spirit	Halfus Wyrmbreaker (H) The Bastion of Twilight
Wand	Finkle's Mixer Upper	Mastery → Haste	Chimaeron (H) Blackwing Descent

This best in slot list uses items from Throne of the Four Winds, which drops items with random affixes, making them harder to obtain than other gear. Below are a few alternatives you can wear if you don't have them yet, but you will need to reforge into more spirit to reach the hit cap.

• Valiona's Medallion — Wear this if you are unable to get Planetary Amulet of the Undertow.
• Belt of Arcane Storms or X-Tron Duct Tape — Wear one of these if you are unable to get Soul Breath Belt of the Undertow.
• Security Measure Alpha — Wear this if you are unable to get Planetary Band of the Undertow.